Some code refactor for better performance of `Avro-Extension` (#4092)

* 1. Collections.singletonList instand of Arrays.asList; 2. close FSDataInputStream/ByteBufferInputStream for releasing resource; 3. convert com.google.common.base.Function into java.util.function.Function; 4. others code refactor

* Put each param on its own line for  code style

* Revert GenericRecordAsMap back about `Function`

extensions-core/avro-extensions/src/main/java/io/druid/data/input/AvroStreamInputRowParser.java

@@ -53,8 +53,13 @@ public class AvroStreamInputRowParser implements ByteBufferInputRowParser
     return parseGenericRecord(avroBytesDecoder.parse(input), parseSpec, dimensions, false, false);
   }
 
-  protected static InputRow parseGenericRecord(GenericRecord record, ParseSpec parseSpec, List<String> dimensions,
+  protected static InputRow parseGenericRecord(
-                                               boolean fromPigAvroStorage, boolean binaryAsString)
+      GenericRecord record,
+      ParseSpec parseSpec,
+      List<String> dimensions,
+      boolean fromPigAvroStorage,
+      boolean binaryAsString
+  )
   {
     GenericRecordAsMap genericRecordAsMap = new GenericRecordAsMap(record, fromPigAvroStorage, binaryAsString);
     TimestampSpec timestampSpec = parseSpec.getTimestampSpec();

extensions-core/avro-extensions/src/main/java/io/druid/data/input/avro/AvroExtensionsModule.java

@@ -36,7 +36,7 @@ import org.schemarepo.ValidatorFactory;
 import org.schemarepo.json.GsonJsonUtil;
 import org.schemarepo.json.JsonUtil;
 
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 
 public class AvroExtensionsModule implements DruidModule
@@ -46,7 +46,7 @@ public class AvroExtensionsModule implements DruidModule
   @Override
   public List<? extends Module> getJacksonModules()
   {
-    return Arrays.asList(
+    return Collections.singletonList(
         new SimpleModule("AvroInputRowParserModule")
             .registerSubtypes(
                 new NamedType(AvroStreamInputRowParser.class, "avro_stream"),

extensions-core/avro-extensions/src/main/java/io/druid/data/input/avro/AvroValueInputFormat.java

@@ -18,6 +18,7 @@
  */
 package io.druid.data.input.avro;
 
+import io.druid.java.util.common.logger.Logger;
 import org.apache.avro.Schema;
 import org.apache.avro.generic.GenericRecord;
 import org.apache.avro.mapreduce.AvroJob;
@@ -31,8 +32,6 @@ import org.apache.hadoop.mapreduce.RecordReader;
 import org.apache.hadoop.mapreduce.TaskAttemptContext;
 import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
 
-import io.druid.java.util.common.logger.Logger;
-
 import java.io.IOException;
 
 public class AvroValueInputFormat extends FileInputFormat<NullWritable, GenericRecord>
@@ -55,13 +54,10 @@ public class AvroValueInputFormat extends FileInputFormat<NullWritable, GenericR
       String schemaFilePath = context.getConfiguration().get(CONF_INPUT_VALUE_SCHEMA_PATH);
       if (StringUtils.isNotBlank(schemaFilePath)) {
         log.info("Using file: %s as reader schema.", schemaFilePath);
-        FSDataInputStream inputStream = FileSystem.get(context.getConfiguration()).open(new Path(schemaFilePath));
+        try (FSDataInputStream inputStream =
-        try {
+                 FileSystem.get(context.getConfiguration()).open(new Path(schemaFilePath))) {
           readerSchema = new Schema.Parser().parse(inputStream);
         }
-        finally {
-          inputStream.close();
-        }
       }
     }
 

extensions-core/avro-extensions/src/main/java/io/druid/data/input/avro/InlineSchemaAvroBytesDecoder.java

@@ -48,6 +48,7 @@ public class InlineSchemaAvroBytesDecoder implements AvroBytesDecoder
 
   private final Schema schemaObj;
   private final Map<String, Object> schema;
+  private final DatumReader<GenericRecord> reader;
 
   @JsonCreator
   public InlineSchemaAvroBytesDecoder(
@@ -61,7 +62,8 @@ public class InlineSchemaAvroBytesDecoder implements AvroBytesDecoder
     String schemaStr = mapper.writeValueAsString(schema);
 
     LOGGER.info("Schema string [%s]", schemaStr);
-    schemaObj = new Schema.Parser().parse(schemaStr);
+    this.schemaObj = new Schema.Parser().parse(schemaStr);
+    this.reader = new GenericDatumReader<>(this.schemaObj);
   }
 
   //For UT only
@@ -69,6 +71,7 @@ public class InlineSchemaAvroBytesDecoder implements AvroBytesDecoder
   InlineSchemaAvroBytesDecoder(Schema schemaObj)
   {
     this.schemaObj = schemaObj;
+    this.reader = new GenericDatumReader<>(schemaObj);
     this.schema = null;
   }
 
@@ -81,9 +84,7 @@ public class InlineSchemaAvroBytesDecoder implements AvroBytesDecoder
   @Override
   public GenericRecord parse(ByteBuffer bytes)
   {
-    DatumReader<GenericRecord> reader = new GenericDatumReader<GenericRecord>(schemaObj);
+    try (ByteBufferInputStream inputStream = new ByteBufferInputStream(Collections.singletonList(bytes))) {
-    ByteBufferInputStream inputStream = new ByteBufferInputStream(Collections.singletonList(bytes));
-    try {
       return reader.read(null, DecoderFactory.get().binaryDecoder(inputStream, null));
     }
     catch (EOFException eof) {

extensions-core/avro-extensions/src/main/java/io/druid/data/input/avro/InlineSchemasAvroBytesDecoder.java

@@ -72,7 +72,6 @@ public class InlineSchemasAvroBytesDecoder implements AvroBytesDecoder
 
       Map<String, Object> schema = e.getValue();
       String schemaStr = mapper.writeValueAsString(schema);
-      ;
 
       LOGGER.info("Schema string [%s] = [%s]", id, schemaStr);
       schemaObjs.put(id, new Schema.Parser().parse(schemaStr));
@@ -116,10 +115,8 @@ public class InlineSchemasAvroBytesDecoder implements AvroBytesDecoder
       throw new ParseException("Failed to find schema for id [%s]", schemaId);
     }
 
-    try {
+    DatumReader<GenericRecord> reader = new GenericDatumReader<>(schemaObj);
-      DatumReader<GenericRecord> reader = new GenericDatumReader<GenericRecord>(schemaObj);
+    try (ByteBufferInputStream inputStream = new ByteBufferInputStream(Collections.singletonList(bytes))) {
-      ByteBufferInputStream inputStream = new ByteBufferInputStream(Collections.singletonList(bytes));
-
       return reader.read(null, DecoderFactory.get().binaryDecoder(inputStream, null));
     }
     catch (EOFException eof) {

extensions-core/avro-extensions/src/main/java/io/druid/data/input/avro/SchemaRegistryBasedAvroBytesDecoder.java

@@ -47,7 +47,8 @@ public class SchemaRegistryBasedAvroBytesDecoder implements AvroBytesDecoder
   }
 
   //For UT only
-  @VisibleForTesting SchemaRegistryBasedAvroBytesDecoder(SchemaRegistryClient registry)
+  @VisibleForTesting
+  SchemaRegistryBasedAvroBytesDecoder(SchemaRegistryClient registry)
   {
     this.registry = registry;
   }
@@ -63,7 +64,8 @@ public class SchemaRegistryBasedAvroBytesDecoder implements AvroBytesDecoder
       Schema schema = registry.getByID(id);
       DatumReader<GenericRecord> reader = new GenericDatumReader<>(schema);
       return reader.read(null, DecoderFactory.get().binaryDecoder(bytes.array(), offset, length, null));
-    } catch (Exception e) {
+    }
+    catch (Exception e) {
       throw new ParseException(e, "Fail to decode avro message!");
     }
   }
@@ -81,7 +83,6 @@ public class SchemaRegistryBasedAvroBytesDecoder implements AvroBytesDecoder
     SchemaRegistryBasedAvroBytesDecoder that = (SchemaRegistryBasedAvroBytesDecoder) o;
 
     return registry != null ? registry.equals(that.registry) : that.registry == null;
-
   }
 
   @Override

extensions-core/avro-extensions/src/main/java/io/druid/data/input/avro/SchemaRepoBasedAvroBytesDecoder.java

@@ -52,7 +52,7 @@ public class SchemaRepoBasedAvroBytesDecoder<SUBJECT, ID> implements AvroBytesDe
   {
     this.subjectAndIdConverter = subjectAndIdConverter;
     this.schemaRepository = schemaRepository;
-    typedRepository = new TypedSchemaRepository<ID, Schema, SUBJECT>(
+    this.typedRepository = new TypedSchemaRepository<>(
         schemaRepository,
         subjectAndIdConverter.getIdConverter(),
         new AvroSchemaConverter(false),
@@ -77,9 +77,8 @@ public class SchemaRepoBasedAvroBytesDecoder<SUBJECT, ID> implements AvroBytesDe
   {
     Pair<SUBJECT, ID> subjectAndId = subjectAndIdConverter.getSubjectAndId(bytes);
     Schema schema = typedRepository.getSchema(subjectAndId.lhs, subjectAndId.rhs);
-    DatumReader<GenericRecord> reader = new GenericDatumReader<GenericRecord>(schema);
+    DatumReader<GenericRecord> reader = new GenericDatumReader<>(schema);
-    ByteBufferInputStream inputStream = new ByteBufferInputStream(Collections.singletonList(bytes));
+    try (ByteBufferInputStream inputStream = new ByteBufferInputStream(Collections.singletonList(bytes))) {
-    try {
       return reader.read(null, DecoderFactory.get().binaryDecoder(inputStream, null));
     }
     catch (EOFException eof) {

extensions-core/avro-extensions/src/main/java/io/druid/data/input/schemarepo/Avro1124SubjectAndIdConverter.java

@@ -20,9 +20,7 @@ package io.druid.data.input.schemarepo;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
-
 import io.druid.java.util.common.Pair;
-
 import org.schemarepo.api.converter.Converter;
 import org.schemarepo.api.converter.IdentityConverter;
 import org.schemarepo.api.converter.IntegerConverter;
@@ -51,7 +49,7 @@ public class Avro1124SubjectAndIdConverter implements SubjectAndIdConverter<Stri
   @Override
   public Pair<String, Integer> getSubjectAndId(ByteBuffer payload)
   {
-    return new Pair<String, Integer>(topic, payload.getInt());
+    return new Pair<>(topic, payload.getInt());
   }
 
   @Override

extensions-core/avro-extensions/src/main/java/io/druid/data/input/schemarepo/SubjectAndIdConverter.java

@@ -20,9 +20,7 @@ package io.druid.data.input.schemarepo;
 
 import com.fasterxml.jackson.annotation.JsonSubTypes;
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
-
 import io.druid.java.util.common.Pair;
-
 import org.schemarepo.api.converter.Converter;
 
 import java.nio.ByteBuffer;